Aerospace firm gains edge with improved measurement technology

Having a system that assists you with fast measurement time, ease of use and high measurement accuracy is an essential when measuring hundreds of points a day is a regular exercise.

Quickstep Technology is an Australian-listed company that manufactures advanced composites for the Aerospace & Automotive industries. One of their most important contracts is supplying composite parts for the new F-35 Fighter Jet, part of the JSF (Joint Strike Fighter) Project.

Quickstep rely on Laser Tracker technology developed by Leica Geosystems of Switzerland and supplied by Industrial Measurement Solutions here in Australia to produce precise measurements.

Santhan Naidoo, a project officer at Quickstep on the Leica Laser Tracker commented on the importance of the equipment used.

"The Leica Laser Tracker is an essential piece of machinery for the quality team here at Quickstep," said Naidoo.

"We utilise the tracker to measure the Layup tools for the new JSF F-35 Fighter Jets. The Leica Tracker was the only suitable solution which provides us with the portability, aerospace accuracy and generous measurement volume required for our specific task."

Interferometers (IFM's) are used to determine relative distances accurate to the nanometer level. As a laser beam is reflected back from a moving reflective target, the return beam moves and the wave peaks cross each other creating a superposition wave.

This is known as "IFM counting". With it the exact change in distance can be calculated. Not only is this incredibly accurate, but it is almost instantaneous. The issue that confronts manufacturers with standard IFMs is that despite their ability to produce highly accurate relative measurements, they are unable to locate an absolute position in 3D space.

Absolute Distance Meters (ADMs) measure absolute distances and are also extremely accurate but have integration time, which is the time taken to conduct the processes which determines a target's 3D location in space. This is, however, bad for dynamic measurement. Long integration times mean fast moving targets cannot be measured accurately. ADMs can never achieve the dynamic measurement ability of IFM's.

AIFM technology developed exclusively by Leica Geosystems combines both IFM and ADM to produce a laser tracker that can generate precise dynamic 3D coordinate positions. This technology roughly explained; compares the ADM's coordinates and constantly references them to the IFM's relative movement. This is known as Absolute Interferometry (AIFM). This technology is unique to the Leica AT901 Laser Tracker.

This makes the Leica AT901 the most accurate and stable dynamic distancing unit that Leica have created.

When the Laser Tracker is combined with the T-Cam camera and T- Probe hand held probe, according to Naidoo, Quickstep are able to easily "measure hidden points in situations where there is no clear line of sight to the reflector."

Naidoo further notes that: "the complex surfaces of our Layup tools have extremely tight tolerances which conventional laser scanning is not able to achieve."

AIFM with the Leica AT901 has been utilised world-wide for prototyping, tooling inspection and part mating by the aerospace, automotive and large scale manufacturing sectors.

This, as Quickstep have realised, gives manufacturers a significant commercial advantage by early detection of potential problems resulting from poor dimensional control, which in turn helps to ensure that parts are produced to specification first time every time.